Abstract: A method of extracting viable bacterial cells from a soil sample by mixing a dispersant-surfactant solution with a soil sample to form a soil slurry, adding the soil slurry to a centrifuge tube containing a density gradient medium, centrifuging the centrifuge tube to form a solvent layer above the density gradient medium, wherein the solvent layer comprises viable bacterial cells, extracting the solvent layer containing the viable bacterial cells, combining the extracted solvent layer with a PBS solution to form a PBS-cell mixture, filtering the PBS-cell mixture to form a cell filtrate, depositing the cell filtrate into a second centrifuge tube containing a quantity of the density gradient medium, centrifuging the second centrifuge tube to form a second solvent layer comprising the viable bacterial cells, and extracting the second solvent layer from the second centrifuge medium to form a second cell filtrate comprising the viable bacterial cells.